Diazo-light-sensitive copying material



United States Patent O No Drawing. Filed Sept. 23, 1964, Ser. No. 398,779 Claims priority, application Germany, Sept. 25, 1963,

K 8 Claims. (Cl. 96-91) The present invention relates to a diazotype copying material of high light-sensitivity and improved properties. It further relates to new compounds having high lightsensitivity and to methods for their preparation.

In recent years derivatives of p-amino diazonium benzene compounds having considerably higher light-sensitivity than known diazo compounds have received great attention. These compounds owe their increased readiness to bleach to one or several alkoxy groups which are attached in certain positions on the benzene nucleus. The compounds are derivatives of the 1-amino-4-diazohydroquinone-(2,5)-dialkyl-ethers in which the amino group is represented by a nitrogen heterocyclic group such as a morpholino, piperidino or pyrrolidino group. Representatives of such compounds have found considerable practical use. However, with copying materials which have been rendered light-sensitive with these compounds, the advantage of high light-sensitivity goes hand in-hand with certain disadvantages. One of these disadvantages is the poor stability of the color obtained initially on the copies. Some time after development, the color changes in most cases in an undesirable manner. A further disadvantage is the undesirable water-solubility which causes bleeding when water colors are used on the copy. Another disadvantage is the relatively weak colors and the relatively poor quality of the developed image.

Furthermore, copying materials containing an alkylaralkylamino group in the 1-position instead of the nitrogen-heterocyclic groups are known. Such diazonium compounds yield colors which are more water-fast, but which still have relatively low resistance to hue changes. In addition, these colors are of little interest for the diazotype process. Furthermore, these diazonium salts have insufficient solubility in aqueous solutions so that their suitability for coating supports is rather limited and they are incompatible in coating solutions with other substances such as 1,3,6-naphthalene trisulfonic acid sodium salt and 1,3,7-naphthalene trisulfonic acid sodium salt.

Therefore one object of the present invention is to provide a diazotype copying material which overcomes the disadvantages of the prior art.

Another object is to provide new light-sensitive diazonium compounds for diazotype materials.

Another object is to provide a method for preparing the new diazonium compounds and materials.

Other objects will become apparent in the course of the following specification.

The objects of the present invention may be realized by a light-sensitive diazotype copying material having a 3,2945 Patented Dec. 27, 1966 layer which contains a light-sensitive diazonium salt with the following general formula:

IMO-Q01 ILTZX wherein R and R stand for a methyl or ethyl group, R stands for a hydroxyalkyl or a dihydroxyalkyl group with a carbon chain having two to three carbon atoms, and X stands for an anionic acid radical.

The present invention relates both to copying materials which do not contain a coupling component and which consequently must be developed with developer solu-.

tions containing a coupling component, and to the socalled two-component materials which contain an azo coupling component and which therefore can be developed with ammonia gas. The light-sensitive copying layer may be coated on supports normally used for diazotype materials, such as paper, precoated paper, and plastic foils, and may include additives such as anti-yellowing agents and stabilizers.

The present diazonium compounds have not been previously known. They are obtained by hydroxyalkylation of the amino group of an amino-hydroquinone-dialkylether with a 'hydroxyalkyl halide or a dihydroxyalkyl halide, subsequent benzylation of the amino group with a 'benzyl halide, coupling of the obtained tertiary amino compound with a diazonium compound to a dyestutf, reductive fission of the azo group of the dyestuif, isolation of the obtained amino compound, diazotization of the amino compound, and precipitation of the resulting diazonium compound as a salt. These compounds are most advantageously precipitated in the form of a zinc chloride double salt, and it is also in this form that they are used with good results for preparing the light-sensitive cop-ying materials. The borofiuorides of the diazonium compounds may also be used with good results. Compared with the zinc chloride double salts, they have certain advantages with regard to their solubility.

The new diazonium compounds are very soluble in water in the form of double salts, and in solution they are highly compatible with additives normally contained in diazotype coating solutions. A copying material prepared with the new diazonium compounds produces strong colors with the coupling components normally used for the diazotype process. Applied to a cellulose acetate support and used together with a coupling component producing blue dyestuffs, they produce images having outstanding color saturation. The Water-fast properties of the resulting colors are considerably improved.

The following examples are intended to further illustrate the invention and are not intended to limit its scope.

Example I A solution containing the fol-lowing substances per 100.0 ml. was coated on a precoated paper diazotype support material:

2,5 diethoxy 4-(N-2'1hydroxyethyl f N-benzyl)- amino benzene diazonium chloride as the zinc chloride double salt g 1.0 2-hydroxy naphthalene-3-carboxylic acid-di-(2'-hydroxyethyl) amide g 1.2 Citric acid g 5.0 Triethylene glycol ml 3.0 Thiourea g 7.0 Zinc chloride a g 2.0 Isopropanol ml 3.0 Glacial acetic acid ml. 2.0

The paper was dried after coating. After exposure under a negative and development with ammonia gas, the copying material produced an image with strong blue lines which were water-fast and of constant hue.

The diazonium compound was prepared as follows: 800 g. of aminohydroquinone diethyl ether, 225 ml. ethylene chlorohydrin, 450 ml. water, and 450 g. of marble dust were boiled together for four hours while refluxing and stirring constantly. Subsequently, 225 ml. of ethylene chlorohydrin and 450 ml. water were added, and the mixture was refluxed for an additional 24 hours while being stirred. After dilution with 3.7 liters of water and the addition of 280 ml. of benzyl chloride, 150 g. of marble dust were cautiously added while stirring to prevent excessive foaming. The mixture was boiled for two hours and another 280 ml. of benzyl chloride 150 g. of marble dust were carefully added. After an additional ten hours of refluxing and stirring, four liters of a saturated salt solution were added to the hot reaction mixture. The oil layer collecting at the top was removed, heated to 90 C. with 3.3 liters of a saturated salt solution, and then cooled. The oil was again separated, distilled, and vacuum-distilled. The distillate, which boiled between 211 C. and 237 C., but mainly between 234 C. and 237 C., was collected under a pressure of 9 mm. mercury. The yield was approximately 900 to 1,000 g.

580 g. of the distillate Were dissolved in 2.58 liters of glacial acetic acid. The diazonium salt prepared by diazotization of 620 g. sodium sulfanilate was added to the solution while stirring. With slight cooling, the temperature was kept below 30 C. After stirring for 1.5 hours, the dark red solution was stirred into 5 to 7 liters of water. The resulting dyestulf was obtained initially in the form of an oil and solidified only after several hours of stirring. It was then drawn off by suction and washed to a neutral pH with water. The yield of moist dyestuff was 700 to 800 g.

500 g. of the moist dyestulf were heated to 80 C. with 6 liters of water and dissolved by the addition of 600 g. of soda. The mixture was heated to 95 C. while 520 g. of sodium dithionite were added while stirring, and subsequently the mixture was allowed to boil for a short period. When the dyestuff had been completely reduced, the aqueous solution was poured off after sufficient cooling and the remaining brown oil was dissolved in 550 ml. of 25% sulfuric acid. 10 g. of decolorizing carbon were added and the solution was filtered. While adding 2.5 kg. crushed ice and stirring, the filtrate was diazotized with approximately 300 ml. of 2 N sodium nitrate solution which was slowly added at C. to C. After a double filtration process using 20 g. of decolorizing carbon each time, the diazonium compound was precipitated as a zinc chloride double salt by the slow addition of 400 ml. of a aqueous solution of zinc chloride, 600 m1. of a saturated salt solution, and finally, 10% by volume of common salt. The precipitate was initially oily but solidifiedafter prolonged stirring. The diazonium compound was drawn off by suction and The yield I l-C Hz-CHaOH N Cl-l/ZZHCI;

Example 2 To prepare the coating solution, a zinc chloride double salt of the diazonium compound mentioned in Example 1 was replaced by the fiuoborate of the same compound. Otherwise, the process was the same as described in Example 1. The copying material produced results similar to that of Example 1.

The fiuoborate was prepared as follows: 200 g. of moist Zinc chloride double salt of the 2,5-diethoxy-4- (N 2-hydroxyethyl-N-benzyl)-amino l-diazo-benzene were dissolved in 6 liters of water at 40 C., filtered through decolorizing carbon, and carefully mixed with 280 ml. of fiuorboric acid (27 B.) to obtain approximately 115-125 g. of fiuoborate salt.

Example 3 An acetyl cellulose foil was coated with the solution consisting of:

Fluoborate of 1-diazo-2,5 diethoxy-4-(N-benzyl-N- After drying the coating, an excellent copying material was obtained. After it was exposed on an original and developed in known manner with ammonia gas, the resulting copy had a bright blue color, was water-fast, and had a constant hue.

Example 4 Instead of the coupling component mentioned in Example 3, 3.8 g. of 2-hydroxy-naphthalene-B-carboxylicacid-2-hydroxyethyl amide was used. The resulting copying material produced water-fast, constant hue copies in a blue tone.

Example 5 A support was sensitized with a solution containing the following substances per ml.:

2,5-dimethoxy-4-(N-2 hydroxyethyl N benzyl)- amino-l-diazobenzene as the zinc chloride double salt g 1.2 2-hydroxy-naphthalene-3-carboxylic-acid-di-(2 hydroxyethyD-amide g 1.2 Citric acid g 5.0 Triethylene glycol ml 3.0

Mixture of 1,3,6-naphthalene-trisulfonic acid sodium salt and 1,3,7-naphthalene-trisulfonic acid sodium After drying of the applied solution, a very good copying material was obtained. After exposure under a negative, it was developed in known manner with ammonia gas. The copy had strong blue lines which were water-fast and of constant hue.

The zinc chloride double salt of the 2,5-dimethoxy-4- (N-Z-hydroxyethyl-N-benzyl)-amino-1-diazo-benzene was prepared in a similar manner to the diazonium compound described in Example 1.

The boiling point of the N-2-hydroxyethyl-N-benzylamino-hydroquinone-dimethylether which was obtained as an intermediate product lay between 231237 C. under reduced pressure (10 mm. mercury). The diazonium zinc chloride double salt prepared from it according to the process described in Example 1 had the formula:

l l -onromorr on o- I IzO1-1/2 ZnClz Example 6 Instead of the coupling component used in Example 5, 2,3-dihydroxy-naphthalene-6-sulfonic-acid sodium salt was used. A copying material with similar properties to that of Example was obtained.

Examples 7 to 11 The diazo compounds described in Examples 7 to 11 were used in coating solutions which were similar to those described in Examples 1 to 6.

Example 7 The zinc chloride double salt of 2,5-diethoxy-4-(N-3- hydroxypropyl-N-benzyl)-amino benzene diazonium chloride was prepared in a manner analogous to that described in Example 1. 181 g. of amino-hydroquinone diethylether, 71 g. of trimethylene chlorohydrin, 100 ml. of water, 100 g. of marble dust were refluxed with heat while stirring for four hours. After theaddition of another '71 g. of tri-methylene chlorohydrin and 100 ml, of water, the mixture was heated for 24 hours. It was drawn off by suction while hot, cooled, and extracted with ether. The ether was distilled off after drying, and the residue was distilled in vacuo. The boiling point was 225255 C. at 9 mm. mercury. 181 g. of 3-hydroxypropylamino-hydroquinone diethylether were obtained. This substance was suspended in 800 ml. of water and benzylated with 139 g. of benzyl chloride and 68 g. of marble dust. The yield of N3-hydroxypropyl-N-benzyl-amino hydroquinone diethylether was 195 g. The boiling point was 245-257 C. at 8 mm. mercury. 164.5 g. of this compound were coupled with diazotized sulfanilic acid to form a dyestufi which was subsequently reduced with sodium dithionite in alkaline solution. 90 g. of the resulting base were diazotized in 400 ml. of 25% sulfuric acid with 200 ml. of a 2 N sodium nitrite solution at 510 C. After filtering through decolorizing carbon, the Zinc chloride double salt of the diazonium compound was precipitated with a 10% aqueous solution of zinc chloride and sodium chloride. It was initially oily, but it solidified after prolonged stirring. By dissolving the compound in water and allowing it to crystallize, a yellow, sandy product was obtained. The yield was 66 g. The obtained double salt corresponded to the formula:

Example 8 zinc chloride double salt obtained from this compound corresponded to the formula:

Example 9 The zinc chloride double salt of 2,5-diethoxy-4-(N-2- hydroxy propyl N benyl)-amino-benzene diazonium chloride was prepared from the amino hydroquinonediethylether and 1 chloropropauol (2). Benzylation, coupling to form a dyestuff, reduction, isolation of the base, and diazotization were carried out in the same way as described in Example 7 in connection with the preparation of the 2,5-diethoxy-4-(n-3'-hydroxypropyl-N-benzyl)-amino-1-diazo benzene. 2-hydroxypropylamino-hydroquinone-diethylether with a boiling point of 198208 C. at 8 mm. mercury and N-2'-hydroxypropyl-N-benzylamino-hydroquinone diethylether with a boiling point of 2282.38 C. at 11 mm. mercury were obtained as intermediate products. The diazonium compound was obtained as a yellow sandy zinc chloride double salt. It corresponded to the formula:

Example 10 The zinc chloride double salt of the 2,5-dimethoxy-4- (N 2 hydroxypropyl-N-benzyl)-amino-1-diazobenzeue was prepared as described in Example 9. 2-hydroxypropylamino-hydroquinone-dimethylether with a boiling point of 192-210 C. at 7 mm. mercury and N-2'-hydroxypropyl N benzylamino-hydroquinone-dimethylether with a boiling point of 230245 C. at mm. mercury were obtained as intermediate products. The diazonium compound was obtained as the zinc chloride double salt. It corresponded to the formula:

I'V CLl/ZZnCl,

Example 11 The zinc chloride double salt of the 2,5-diethoxy-4- (2,3'-dihydroxypropyl-N-benzyl)-amino-1-diazo benzene was prepared in a similar manner as the compound described above. Amino hydroquinone diethylether and alpha-monochlorohydrin were used as starting materials.

The 2,3 dihydroxypropylamino-hydroquinone-diethylether which was obtained as an intermediate product boiled in a vacuum (9 mm. mercury) at 238-246 C. The N 2,3' dihydroxypropyl N benzylaminohydroquinone-diethylether obtained therefrom as a further intermediate product boiled at a pressure of 8 mm. mercury between 236 and 255 C., mainly between 243 and 249 C. The diazonium chloride-zinc chloride double salt which was obtained corresponded to the formula:

O I 02H; CzHsO- ILgCl-l/ZZDC]:

Example 12 double salt g 1.2 Citric acid g 5.0 Triethylene glycol ml 3.0 Thiourea ml 7.0

Mixture of 1,3,6-naphthalene-trisulfonic acid sodium salt and l,3,7-naphthalenetrisulfonic acid sodium salt g 4.0 2-hydroxynaphthalene 3 carboxylic acid di-(p-hy droxyethyl)-amide g 1.2 Zinc chloride g 2.0

The coated paper was dried to produce an excellent copying paper. After exposure under a negative and development with ammonia gas, a positive image was obtained with blue lines. It was waterfast and of constant hue.

The zinc chloride double salt of the 2,5-dimethoxy-4- (N 2',3-dihydroxypropyl-N-benzyl)-amino-l-diazo benzene was prepared in the same way as the compound described in Example 11. The boiling point of the N-2,3- dihydroxypropyl N benzyl amino hydroquinone dimethylether which was obtained as an intermediate product was between 240250 C. in vacuo (8 mm. mercury). The diazonium salt was obtained as a double salt. It corresponded to the formula:

I OCH; C11 0 It is apparent that the described examples are capable of many variations and modifications. All such variations and modifications are to be included within the scope of the present invention.

What is claimed is:

1. A light-sensitive copying material for the diazotype process, which comprises a support and a light-sensitive diazo compound coated on said support, said compound having the formula:

diazo compound coated on said support, said compound having the formula:

where R and R are members selected from the group consisting of methyl and ethyl, R is an hydroxyalkyl group with two to three carbon atoms and one to two hydroxyl groups, and X is an anionic acid radical.

3. A light-sensitive copying material for the diazotype process, which comprises a support and a light-sensitive diazo compound coated on said support, said compound being 2,5 diethoxy 4 (N 2 hydroxyethyl N- benzyl)-amino-benzene diazonium chloride, zinc chlo ride double salt.

4. A light-sensitive copying material for the diazotype process, Which comprises a support and a light-sensitive diazo compound coated on said support, said compound being 2,5 diethoxy 4 (N 2' hydroxyethyl N- benzyl)-amino-benzene diazonium fluoborate.

5. A light-sensitive copying material for the diazotype process which comprises a support and a light-sensitive diazo compound coated on said support, said compound being 2,5 diethoxy 4 (N 3' hydroxypropyl N- benzy1)-amino-benzene diazonium chloride, zinc chloride double salt.

6. A light-sensitive copying material for the diazotype process, which comprises a support and a light-sensitive diazo compound coated on said support, said compound being 2,5 dicthoxy 4 (N 2' hydroxypropyl N- benzyl)-amino-benzene diazonium chloride, zinc chloride double salt.

7. A light-sensitive copying material for the diazotype process Which comprises a support and a light-sensitive diazo compound coated on said support, said compound 19 being 2,5 dimethoxy 4 (N 2,3' dihydroxypropyl- N-benzyD-amino-benzene diazonium chloride, zinc chloride double salt.

8. A light-sensitive copying material for the diazotype process, which comprises a support and a light-sensitive diazo compound coated on said support, said compound being 2,5 dimethoxy 4 (N 2' hydroxyethyl N- benZyD-aminQ-benZene diazonium chloride, zinc chloride double salt.

References Cited by the Examiner UNITED STATES PATENTS 2,649,373 8/1953 Neugebauer 96- 91 2,980,534 4/1961 Printy et al. 9691 2,993,803 7/1961 Sulich 117-34 3,061,453 10/1962 Rogers 11734 3,081,166 3/1963 Loon et a1 96-91 3,140,180 7/1964 Fritz 9691 3,164,469 1/1965 Behmenburg et a1. 9691 3,189,451 6/1965 Reichel 9691 NORMAN G. TORCHIN, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,294,541 December 27, 1966 Georg Werner et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, lines 3 to 16, the lower portion of the formula should appear as shown below instead of as in the patent:

column 4, line 45, for "naphthalene-Z-carbox" read naphthalene-S-carbox Signed and sealed this 26th day of September 1967.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. A LIGHT-SENSITIVE COPYING MATERIAL FOR THE DIAZOTYPE PROCESS, WHICH COMPRISES A SUPPORT AND A LIGHT-SENSITIVE DIAZO COMPOUND COATED ON SAID SUPPORT, SAID COMPOUND HAVING THE FORMULA: 